EDGE: Explorer of Diffuse emission and Gamma-ray burst Explosions
Jan-Willem den Herder (SRON) , L. Piro (INAF-Rome), T. Ohashi (Tokyo Metropolitan University), C. Kouveliotou (MSFC) on behalf of the EDGE consortium
How structures on various scales formed and evolved from the early Universe up to present time is a fundamental question of astrophysical cosmology. EDGE will trace the cosmic history of the baryons from the early generations of massive star by Gamma-Ray Burst (GRB) explosions, through the period of cluster formation, down to very low redshifts, when between a third and one half of the baryons are expected to reside in cosmic filaments undergoing gravitational collapse by dark matter (Warm Hot Intragalactic Medium: WHIM). In addition EDGE, with its unprecedented observational capabilities, will provide key results on several other topics including: the study of feedback mechanisms into the Interstellar Medium (Supernova Remnants, galaxy/Active Galactic Nuclei outflows), constraints on the Dark Matter and Dark Energy content of the Universe (through clusters and GRBs), equation of state of the densest matter (neutron stars), GRB physics, upper limits on light dark matter particles, accurate measurement of the geometry of space-time by measuring X-ray afterglows of black hole mergers detected through gravitational waves, Active Galactic Nuclei and stellar population surveys, and Solar System physics. The science is feasible with a medium class mission using existing technology combined with innovative instrumental and observational capabilities on a single satellite by: a) observing with fast reaction Gamma-Ray Bursts with a high spectral resolution (R 500). This enables the study of their (star-forming) environment from the Dark to the local Universe and the use of GRB as back light of large scale cosmological structures b) Observing and surveying extended sources (clusters, WHIM) with high sensitivity using two wide field of view X-ray telescopes (one with a high angular resolution and the other with a high spectral resolution). The mission concept includes four main instruments: a Wide-field Spectrometer with excellent energy resolution (3 eV, 1 eV goal), a Wide-Field Imager with high angular resolution (15”) constant over the full 1.4 degree field of view, and a Wide Field Monitor with a FOV of ¼ of the sky, which will trigger the fast repointing. Extension of its energy response up to 1 MeV will be achieved with a GRB detector with no imaging capability. This mission is proposed to ESA as part of the Cosmic Vision call. We will describe the science drivers and the payload of this mission.